Laser scanning confocal microscopy (LSCM) will be a cornerstone of all five projects within this P01 Program. Specific applications for this instrument are outlined in the Budget Justification and are discussed in greater detail within each of the five project proposals. As such, we are requesting funds for a state-of-the-art Zeiss Axiovert 200M motorized inverted microscope equipped with the Pascal 5 Laser Scanning Microscope module, motorized emission/excitation wheels, motorized scanning stage, digital CCD cameras, and computer with two flat screen monitors. This instrument will be housed exclusively within the BSL3/BSL3-animal facility for work on the virulent Schu4 strain of Francisella tularensis. Funds for an annual service contract, maintenance, and salary for a one-half-time technician to oversee general operation of the instrument will be provided by the Department of Microbiology and the Dean's office of U.T. Southwestern Medical Center.